being systematic about solving problems
This is relevant from primary school all the way through high school and university and beyond, finding
solutions in all kinds of professional tasks — science, business, design, engineering, computers, policy
making and management — pretty much any field which requires thought and initiative rather than simply
carrying out repetitive set actions. It is one of the ways we analyse and talk about the world.
It is also at the centre of the maths syllabus, every year from infants to year 12.
If you are in primary school … some of the language I am using here is talking to older students, don’t worry about that — skip those parts — you have plenty of time to learn about that stuff later.
Just have a go, jump into one of the easier problems in this collection: problemsolvingwall200.pdf — they go from primary school to senior high school level — find one you think might be interesting.
If you are further along this journey dig a little deeper. Return to it later, much of the maths you
are studying is related to these ideas. By the time you leave school I hope you have a strong
sense of how to approach a problem more formally, how to use a mathematical model to understand
the relationships and find a solution.
a summary of the main ideas
What exactly is being asked?
what is the problem?
why are you being asked to solve it?
it is very easy to jump into answering something else entirely!
you might have to dig a little to find the actual question that needs answering.
in a test — make sure you get this from the question!
in life — the context, and the audience, suggests the kind of response required.
in each of these the argument backing your result is the main part of your answer.
is a number (or numbers) required?
for measurements — what are the units?
an exact value? — hence a fraction or surd — this is the ‘default’
do you also need an approximate value? — a decimal — how accurate is the data given?
give it (them) a name — a pronumeral, it is the most important ‘unknown’!
is a diagram, picture or some graphical representation required?
in school, and in every other application of maths, it is the argument, the reasoning, that is important — the justification for your conclusions, the reason someone should believe what you are saying.
we say “Show your working!!” — what this means is explain how you got your answer, make a clear argument that someone else could follow (someone who already understands the topic, and the notation you are using, and who is familiar with the rules you have covered in class)
What is required to find this value? (or values, or details in a diagram or graph)
What facts have you been given?
write them down as equations, or draw them
there might be some extra, unimportant, facts given
as you work on the problem, keep going back to the question
some facts might be a bit hidden
some later phrase might clarify what an earlier one said
some algebra might reveal something is impossible, or fixed, and that can resolve issues about what the question really meant, perhaps clear up ambiguities
consider each phrase in the question — break the question into the different ‘facts’ presented
find any facts given in pictures, graphs or diagrams
lengths, distances, areas or other measurements labelled with values, units or names
angles labelled with values or names … look for any right angles and parallel lines.
note any shapes, angles or lengths that are equivalent or described
fill in details …
are any shapes shown also described in the question? what are you told about them!
label points fully … eg`quad(2,5)quad`or`quad(a,0)`
label axes, directions and scales
label lines on graphs with their equations
thoughtfully and succinctly marking these names and labels will help understand the problem
draw diagrams, or label the ones given, with any facts you have been told
look for geometrical facts connecting the values (known or named) in any diagram
if you are looking for angles … think parallel lines and other angle rules
if you are looking for distances … think pythagoras, similar triangles, sides of shapes and other rules about length
if the problem mixes angles and lengths trigonometry ratios might be important
write down any relationship between what you are given and the unknowns you have named (you have probably already done most of this, if you have been careful so far)
perhaps some digging will be required, to find more ‘facts’ or discover other relationships
perhaps you need to use some known laws or properties, especially in science questions or topics with specific methods you learnt
be familiar with where to find formula you have been shown (see the notes about
formula sheets below in a test, or know were reference material is — in your textbooks or online)
Combine these facts and relationships
here is the main algebra part
substitute known properties of variables into equations to find new facts, new equations
combine two equations, two facts, to find a new one with fewer variables
logically you are trying to eliminate some variables to find relationships between the others
then step by step get a particular value for one of the ‘unknowns’
now substitute that value into the known facts — the equations and diagrams you have drawn
then continue, finding other values using earlier ‘facts’ in the same way
this process requires creative manipulation of the different equations
algebra lets you rearrange the known relationships into forms that show new insights
thinking mathematically is recognising which patterns or strategies might lead to a solution
then exploring, following a strategy and with luck simplifying the problem
then going back, adding any new insights to the problem and applying further strategies
learning mathematics involves becoming familiar with many different strategies
applying mathematics to a problem requires translating it into mathematical language
at school level this is usually a combination of algebraic and geometric descriptions
or the language we use about data, the statistical values and ideas that describe it
it is all about being systematic —
assembling what you know, expressing it clearly and succinctly, remembering some rules, doing a bit of
manipulation
then giving an answer to the actual question — always in an appropriate form!
finally — check that your answer is sensible!
Remember: if the question has lots of parts some information will only be needed for one little part
(or not at all).
problem solving in tests
problem questions are often worth more than one mark, and usually each step is a half-mark or so.
make sure you show the person marking everything that you think may be important, and the reasons you made each step in your working … this is basic exam strategy, the marker cannot read your mind.
if you do not get the full answer you will still get marks for getting half way …
if you are running out of time … try outlining the steps you need to take, this can be much faster than working out the details, and it might get most of the marks, but only if very clearly described!
if you are stuck and you have written down all facts you see that are relevant
this will get you some marks if they are the right facts, if you are part way toward a solution
it also allows you to move on and come back later, picking up where you left off
maybe the next time you look at it you will see the way forward
maybe some other question helps you understand or remember something
maybe just thinking about something else lets your mind find the trick you need, the next step, in the background
are in every exam — make sure, during revision, that you are familiar with the one you will be given
where to find each formula
the ‘standard’ uses of each one — the sheet gives you a big hint about which ‘standard’ methods might be asked!!
make sure you know what variables and constants the symbols in these formula represent — they are given in the sheet with very minimal explanation (the title can help!)
there are some simple formula you are expected to know, that are not on the sheet.
you can use rules, results established in earlier questions
remember that you might use the answer to a previous part, even if you could not show it!
this becomes more important as you move through the years … you will start to get multi-part questions that might be ‘show blah blah is true if’ and in the next part you need use that fact.